Worldwide a large number of people suffer sudden cardiac arrest (SCA) events. For instance, in Europe alone there are between 350,000 and 700,000 out of hospital sudden cardiac arrest (SCA) events every year which are frequently witnessed by (untrained) lay people. Cardiopulmonary resuscitation (CPR) is the key life-saving intervention recommended by international guidelines for victims of SCA, where necessary (in about ⅓ of all SCA cases) supplemented by defibrillation using an automatic external defibrillator (AED). CPR involves the delivery of chest compressions (CCs) at a depth of at least 5 cm and at a rate of 100 compressions per minute (cpm), in combination with artificial ventilation (i.e., rescue breaths) to maintain the circulatory flow and oxygen supply to the vital organs in the body of the SCA sufferer until spontaneous circulation returns.
For successful resuscitation it is essential that CPR is performed as soon as possible. Currently, international guidelines recommend that the cardiac arrest situation is recognised within 5-10 sec following the SCA event by performing a breathing check. Prior to 2005, a manual pulse check in addition to the breathing check was recommended by the guidelines for the diagnosis of cardiac arrest. This recommendation was removed from the CPR guidelines due to the unwillingness and the inability of lay rescuers to quickly and correctly perform pulse palpation. Nevertheless, pulse detection is still perceived by the resuscitation community as an important (supplementary) technique for the assessment of the need for CPR in an emergency situation.
With every minute that passes prior to initiating CPR, the probability of saving a victim's life decreases by 10% and after 10 minutes there is almost no chance of successful resuscitation. Moreover, poor CC performance, i.e., insufficient depth, rate and/or duration of CC by lay rescuers is one of the main factors contributing to the reported low post-CPR survival rate for victims of out-of-hospital cardiac arrests, which is between 9.5% and 11.4%.
In addition, challenging terrain (e.g., bush, ice, soft snow, sloping, rocky or uneven ground, etc.), harsh environmental conditions (e.g., snow, mist, fog, rain, low lighting) and safety hazards (e.g., chemical spills, downed power lines, fire, smoke, vehicle traffic, etc.) present significant barriers to the delivery of effective CPR, and may partly contribute to the reported low post-CPR survival rate. For example, performing chest compressions during CPR on an inclined or soft back support surface will produce shallower, less effective compressions, which will lead to poorer survival outcomes. Moreover, current CPR guidelines recommend that prior to initiation of CPR lay rescuers should always check for any potential hazards and should only approach the victim after determining that the scene is safe. This is especially important since many people may act impulsively and place themselves in harm's way, due to difficulties in thinking clearly as a result of the highly stressful emergency situation.
Hence there is a profound need for a solution that can assist lay rescuers in the management of the CPR workflow of bystander lay rescuers and can provide CC guidance to enable them to deliver effective CPR in a timely manner.
Many commercial solutions exist for CPR workflow management and CC guidance during CPR; however, these solutions are primarily aimed at meeting the needs of professional, Basic Life Support (BLS) and Advanced Life Support (ALS) users. In recent times some solutions aimed at lay rescuers have become available or are currently under development.
For example, EP 2 308 450 A1 discloses an apparatus for assisting a rescuer in performing chest compressions during CPR on a victim, the apparatus comprising a pad or other structure configured to be applied to the chest near or at the location at which the rescuer applies force to produce the chest compressions, at least one sensor connected to the pad, the sensor being configured to sense movement of the chest or force applied to the chest, processing circuitry for processing the output of the sensor to determine whether the rescuer is substantially releasing the chest following chest compressions, and at least one prompting element connected to the processing circuitry for providing the rescuer with information as to whether the chest is being substantially released following chest compressions. In particular, the apparatus comprises a bistable mechanical element providing tactile and optionally audible feedback to the rescuer, thereby indicating the beginning and the end of a compression cycle. A drawback of this apparatus is that the feedback provided by the apparatus may be difficult to interpret by a lay rescuer, such that the feedback may not lead to an improvement of the CPR being administered, thus reducing the survival risk of the victim.
US 2008/0171311 A1 discloses a CPR assist glove adapted to provide CPR guidance. The glove contains an accelerometer, a plurality of pressure sensors and an ECG sensor all coupled to a processing unit for processing the sensed parameters and for providing CPR guidance based on the processed parameters to a feedback device such as a display device on the glove or a separate display device of a computer or the like. This however is not ideal. The size of the glove limits the dimensions of the display device that can be incorporated therein, such that the rescuer may struggle to read the guidance on the display device when the hand of the rescuer is placed on the chest of the victim. On the other hand, a separate display device may be bigger but forces the rescuer to look away from the victim, thus hampering the CPR workflow. Moreover, the number of lay rescuers that will routinely carry such a dedicated CPR assist glove is likely to be rather limited.
US 2014/342330 A1 discloses a device for assisting rescuers in performing CPR and a method for managing CPR treatment to a person in need of emergency assistance, which includes capturing one or more images at a scene where the person in need of medical assistance is being treated using one or more cameras at the scene, performing automatic computer-based analysis of the images to identify a quality of treatment provided to the person in need of medical assistance, and using analysis of the images to direct rescuers at the scene of the person in need of medical assistance in performing care for the person in need of medical assistance.
Internet publication “Education & Research Feature—Physician Advocates Medical Innovation with Google Glass”, by Christina Trimble, University of Arkansas for Medical Sciences, Jul. 24, 2013, proposes the use of Google glass to assist individuals in performing CPR on a victim of cardiac arrest.
In addition, recently there has been a proliferation of smart device applications for lay rescuer CPR guidance, e.g., the Pocket First Aid & CPR, the Real time CPR guide and the CPR metronome, which can be obtained in app stores around the world, e.g. the Google Play Store. However, these apps are primarily for training and are unsuitable for real-time CPR guidance because they require continuous user input and interaction, again hampering CPR workflow.